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Radionanomedicine with Hybrid Nanomaterials
Published in Feng Chen, Weibo Cai, Hybrid Nanomaterials, 2017
Upconverting nanoparticles (UCNPs) are very well known to be an ideal nanoparticle for live cells used in vitro and possible in vivo and also can be used for photodynamic therapy (PDT) (Park et al. 2012) (Fig. 9.5). Near- infrared lasers of 980 nm or 800 nm are going to be used for excitation and the lights of visible range are emitted (Bae et al. 2012; Li et al. 2012; Li et al. 2013; Park et al. 2012; Yang et al. 2013c). The usual light-microscopes could be used for tracking the behaviors of the nanoparticles inside the alive cells after real-time or intermittent serial sequential imaging (Bae et al. 2012). The limitation of ordinary particles such as quantum dots is its high energy transfer which deteriorates the cellular viability during in vivo cell imaging (DaCosta et al. 2014; Park et al. 2015; Sedlmeier and Gorris 2015). UCNP can overcome this limitation and is free of the autofluorescence if used in vivo. Also the near-infrared ranged excitation ray can penetrate the inside of the body up to few centimeters; however, the emission light is in the visual (Y/Er/ Yb) or infrared (Gd/Nd/Er/Yb) range and can penetrate only millimeters of the tissues. Scattering and absorption of the emission light and the excitation light (with the lesser amount) will require the injected amount to be higher. Thus, though the UCNP looks inert in the body, the amount of the UCNP needed for in vivo luminescence imaging will be several tens times more than the amount needed for PET imaging.
Nanoparticle Contrast Agents for Medical Imaging
Published in Alok Dhawan, Sanjay Singh, Ashutosh Kumar, Rishi Shanker, Nanobiotechnology, 2018
Rabee Cheheltani, Johoon Kim, Pratap C. Naha, David P. Cormode
Upconverting nanoparticles (UCNPs) take advantage of lanthanide ions to emit light at a lower wavelength than excitation wavelength. One of the advantages of these agents is the high efficiency of the upconversion process that leads to high imaging sensitivity (Lee et al. 2013). Due to the high atomic number and high x-ray attenuation of lanthanides, such UCNPs have been developed with stronger CT contrast properties than iodinated agents. Er3+/Yb3+ or Tm3+/Yb3+ co-doped NaYF4 particles, as well as Er3+-doped Yb2O3, are examples of such CT contrast agents. By including Gd3+ in the formulation, particles can also have MRI applications (Lee et al. 2013).
Controlled Wet Chemical Synthesis of Multifunctional Nanomaterials: Current Status and Future Possibility
Published in Surender Kumar Sharma, Nanohybrids in Environmental & Biomedical Applications, 2019
Navadeep Shrivastava, Surender Kumar Sharma
The major focus of biomedical applications is in upconverting nanoparticles where a near infrared (NIR) laser is used to excite the nanoparticles. NIR downconverting nanoparticles are in focus nowadays. A wide variety of synthesis protocols are on trend for nanoparticles such as co-precipitation, thermal decomposition, hydro(solvo)thermal synthesis, microwave-assisted, combustion synthesis and urea homogeneous precipitation with their competitive advantages/disadvantages (Wang & Liu, 2009; Niu et al., 2014; Zhou et al., 2015). Two different protocols can also be combined for preparation. Postsynthesis processes are used as well for the development of upconversion nanoparticles with controlled particle size, chemical composition or surface functionalization. The most convenient and highly cited method from the beginning for producing ultra-small particles is co-precipitation, which has been used by several groups for the synthesis of nanoparticles (5–10 nm) with better size distribution. While having no need for costly equipment and complicated procedures, this method has a fast growth rate and requires post-annealing processes. In a typical process, a solution of lanthanide salts is injected into a solution of the host material. Examples of hosts used are LaF3, NaYF4, LuPO4 and YbPO4 (Haase & Schäfer, 2011). Particle size and growth rate can be regulated by using capping ligands or chelating agents such as polyvinylpyrrolidone (PVP), polyethylenimine (PEI) or ethylenediaminetetraacetic acid (EDTA) (Dong et al., 2015b). In particular, PEI provides a good platform for direct surface functionalization of nanoparticles with bioligands. However, a heat treatment step is required for post processing, which is one of the disadvantages of this method.
Recent progress at the interface between nanomaterial chirality and liquid crystals
Published in Liquid Crystals Reviews, 2021
Diana P. N. Gonçalves, Marianne E. Prévôt, Şenay Üstünel, Timothy Ogolla, Ahlam Nemati, Sasan Shadpour, Torsten Hegmann
Li et al. [80], for example, studied combining NaYF4:TmYb upconverting nanoparticles (UCNPs) (near infrared, NIR, light conversion to UV-visible), which emit at multiple wavelengths and allow for tuning of (or CPL) by altering the PBG of the CNC films by adding glycerol. While other studies already reported that adding an increasing amount of glycerol to aqueous CNC suspensions and cast as films (by EISA) shifts the maximum wavelength of the band in the reflection spectra from 400 nm (no glycerol) to 800 nm (50% glycerol ratio) due to increase of p in the composite films [81], here, the addition of UCNPs and glycerol made the CPL emission susceptible to humidity, thereby enabling UC-CPL as a sensor for changes in humidity Figure 12.
Nitric oxide release from a photoactive water-soluble ruthenium nitrosyl. Biological effects
Published in Journal of Coordination Chemistry, 2018
Meredith A. Crisalli, Lilian P. Franco, Bruno R. Silva, Alda K. M. Holanda, Lusiane M. Bendhack, Roberto S. Da Silva, Peter C. Ford
Nonetheless, a realistic evaluation of the present system has to take into consideration that the short wavelength necessary to trigger NO release from 1 would have poor penetration through living tissue. For this reason, strategies that can utilize tissue penetrating near infrared (NIR) light such the use of antennas such as upconverting nanoparticles that can be activated by multiphoton NIR excitation need to be employed. Notably, the pendant carboxylate groups of 1 besides providing aqueous solubility also provide ample opportunity for further conjugation with groups like cell-targeting peptide [46] or with antennas such as nanomaterials with desirable photophysical properties [13, 47]. These studies are ongoing.